During the year of grant support requested, the purified monomers of the human alpha-, beta- and kappa-caseins will be characterized as to size (molecular weight) and approximate shape (sphere or ellipsoid of particular dimensions) by means of analytical ultracentrifugation and viscosity. This will also require a determination of the specific gravity (or density) of the monomer proteins in solution. This information is important in determining possible modes of interaction to form micellar aggregates. The amino acid composition of each monomer will also be determined and a beginning may be made on the measurement of calcium binding to each of the human caseins under a variety of ionic environmental conditions.